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Zoom lens and image pickup apparatus including the same

a technology of zoom lens and image pickup, which is applied in the field of zoom lens, can solve the problems of difficult downsizing of the camera, difficult to obtain high optical performance over the entire zoom range, and complicated lens barrel structure, etc., and achieves high optical performance, wide range, and high zoom ratio

Active Publication Date: 2012-07-10
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is a zoom lens that has a compact lens system, a wide field angle, and a high zoom ratio. It includes three lens units that move during zooming and a secondary aperture with a constant aperture diameter. The second lens unit has positive refractive powers at both its closest positions to the object and image sides, and satisfies a specific condition. The zoom lens has high optical performance over the entire zoom range.

Problems solved by technology

However, if the refractive power of each lens unit is simply enhanced for realizing a wide field angle and a high zoom ratio with a small size of the entire system of the zoom lens, for example, aberration variation due to zooming increases so that it becomes difficult to obtain high optical performance over the entire zoom range.
Therefore, in order to obtain a desired retractable length, a complicated lens barrel structure is required.
If the number of lenses constituting each lens unit is increased, the total lens length in the retracted state increases so that it becomes difficult to downsize the camera.

Method used

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  • Zoom lens and image pickup apparatus including the same
  • Zoom lens and image pickup apparatus including the same
  • Zoom lens and image pickup apparatus including the same

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Experimental program
Comparison scheme
Effect test

numerical embodiment 1

Unit: mm

[0072]

Surface dataSurfaceNumberrdndνd 1*∞1.201.8495440.1 2*5.5482.31 3 10.2931.601.9228618.9 4 21.778(Variable) 5 0.50(Aperture) 6*6.4862.301.7433049.3 7*275.0400.20 8 6.7681.651.7725049.6 9 48.2000.502.0006925.510 3.9871.6511 11.9811.401.8348142.712 65.4100.6013 Secondary(Variable)aperture14 16.3911.701.4874970.215 −21.482(Variable)16 ∞0.951.5163364.117 ∞1.05Image∞planeAspherical surface dataFirst surfaceK = 7.54512e+008B = 1.88618e−004C = 6.44928e−006D = −6.21908e−008E = −6.47132e−014Second surfaceK = 2.34707e+000B = 1.05626e−003C = −2.43088e−005D = 6.21908e−008E = −1.85511e−008Sixth surfaceK = −1.83908e−001B = −2.23674e−004C = 2.76144e−009D = −1.83041e−007E = −4.63046e−009Seventh surfaceK = 4.86718e+003B = −5.35130e−005C = −6.71896e−007D = 4.03626e−007E = −4.23510e−008Various dataZoom ratio 3.80Wide angleIntermediateTelephotoFocal length5.009.7019.00F number2.064.005.50Field angle34.2121.7811.53Image height3.403.883.88Total lens 38.7235.9243.05lengthBF3.953.853.67d415.466...

numerical embodiment 2

Unit: mm

[0073]

Surface dataSurfaceNumberrdndνd 1*12734.7631.101.8495440.1 2*5.3712.47 3 10.5891.601.9228618.9 4 23.646(Variable) 5 0.50(Aperture) 6*6.4882.301.7433049.3 7*272.6760.30 8 7.1431.751.8061040.9 9 −29.3540.502.0006925.510 4.1731.4511 12.2961.201.8348142.712 95.8011.3013 Secondary(Variable)aperture14 14.8911.701.5831359.415 −35.565(Variable)16 ∞0.951.5163364.117 ∞1.05Image∞planeAspherical surface dataFirst surfaceK = −7.54512e+008B = −4.96945e−005C = 9.80089e−007D = −2.93189e−009Second surfaceK = −1.84750e+000B = 8.96608e−004C = −1.32261e−005D = 3.88560e−007E = −4.26518e−009Sixth surfaceK = 6.66357e−002B = −1.78667e−004C = 2.32749e−006D = 2.74312e−007E = 1.90745e−008Seventh surfaceK = −7.13425e+002B = 1.81194e−004C = 1.34182e−005D = 7.10950e−007Various dataZoom ratio 3.88Wide angleIntermediateTelephotoFocal length4.909.6319.00F number2.064.605.70Field angle34.7621.9211.53Image height3.403.883.88Total lens length37.7935.5343.44BF3.953.863.67d414.636.021.62d133.049.4821.98d15...

numerical embodiment 3

Unit: mm

[0074]

Surface dataSurfaceNumberrdndνd 1*∞1.151.8495440.1 2* 5.6732.78 3 11.4091.601.9459518.0 4 24.393(Variable) 5 0.50(Aperture) 6* 7.4632.251.7433049.3 7*108.420 0.17 8  6.1341.651.5831359.4 9 32.1730.501.8051825.410  4.2121.6011 18.3721.351.6968055.512 − 90.741 0.8013 Secondary(Variable)aperture14 25.6811.701.6968055.515 − 27.341 (Variable)16 ∞0.871.5163364.117 ∞1.02Image∞planeAspherical surface dataFirst surfaceK = −7.54512e+008B = −2.87622e−004C = 1.08335e−005D = −1.50001e−007E = 4.89614e−010Second surfaceK = −2.42402e+000B = 8.66826e−004C = −1.78319e−005D = 1.00852e−006E = −2.01684e−008Sixth surfaceK = −9.46174e−002B = −1.28264e−004 C = −1.33414e−007 D = −2.18122e−007E = 7.36760e−009Seventh surfaceK = 6.28037e+002B = −2.77000e−005C = −7.04871e−007D = −2.44718e−007Various dataZoom ratio 3.66Wide angleIntermediateTelephotoFocal length5.009.5018.30F number2.064.005.40Field angle34.2222.1911.96Image height3.403.883.88Total lens length42.8038.9845.52BF3.793.753.69d417.527.6...

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PUM

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Abstract

Provided is a zoom lens including, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a third lens unit having a positive refractive power, all the lens units moving during zooming; and a secondary aperture having a constant aperture diameter disposed on the image side of the second lens unit, in which the second lens unit includes lens components having a positive refractive powers disposed at a position closest to the object side and a position closest to the image side, and a distance (dd) on an optical axis between a lens surface closest to the image side in the second lens unit and the secondary aperture, and a focal length (fw) of the entire zoom lens at a wide angle end are appropriately set.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a zoom lens, which is suitable for an image pickup apparatus, such as a digital still camera, a video camera, and a TV camera.[0003]2. Description of the Related Art[0004]In recent years, an image pickup apparatus (camera) using a solid-state image pickup element, such as a video camera and a digital still camera has been downsized and developed to have high-performance. Then, due to the downsizing and high-performance of the image pickup apparatus, an optical system used therefor is required to include a wide field angle and to be a small zoom lens with a high zoom ratio, a large aperture ratio, and high optical performance. This type of camera includes various optical elements such as a low pass filter and a color correction filter disposed between the lens rearmost part and the image pickup element. Therefore, the zoom lens used for the image pickup apparatus is required to have a rel...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): G02B15/14
CPCG02B13/22G02B15/177G02B15/143507
Inventor SARUWATARI, HIROSHI
Owner CANON KK
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